Aggregates are commonly used to speed up queries in data warehousing. Whenever time is one of the attributes, it is common to maintain pre-computed aggregates on coarser units of time like hours and days. Depending on the granularity of time used in queries, either hourly or daily aggregates may be used. However, there are cases where it may not be obviously possible to use daily aggregates even though the granularity of time referenced in the query is a day. One example is when daily aggregates are computed each day on GMT boundary. If an incoming query references time in GMT and the granularity of time referenced in query is not finer than a day, it is straightforward to use daily aggregates. However, if the incoming query references time in a different time zone, even though the granularity of incoming query is a day, it is not straightforward to use daily aggregates and one may end up using hourly aggregates. A similar problem results even if the time zone is GMT if the user would want to consider the start of day as 09:00:00 hours rather than 00:00:00 hours.